判断计算机当前的网络是否连接

using system.runtime.interopservices;
[dllimport("wininet.dll")]

        private extern static bool internetgetconnectedstate(out int connectiondescription, int reservedvalue);

private static bool isconnected()
        {

            int i = 0;

            bool state = internetgetconnectedstate(out i, 0);

            return state;

        }

        static void main(string[] args)
        {
            console.writeline(isconnected().tostring());
        }